Aqueous acidic plating baths for electrolytic deposition of copper are used for manufacturing of printed circuit boards and IC substrates where fine structures like trenches, through holes (TH), blind micro vias (BMV) and pillar bumps need to be filled or build up with copper. Another application of such electrolytic deposition of copper is filling of recessed structures such as through silicon vias (TSV) and dual damascene plating or forming redistribution layers (RDL) and pillar bumps in and on semiconducting substrates. Still another application which is becoming more demanding is filling through glass vias, i.e. holes and related recessed structures in glass substrates with copper or copper alloys by electroplating.
EP 2 199 315 A1 reports that alkoxylated polyalkanolamines can be used in the electrolytic copper deposition of recessed structures such as vias and trenches.
U.S. Pat. No. 6,800,188 B2 relates to levellers formed by condensation of glycidyl ethers and amine compounds and the respective ammonium derivatives thereof to be used in electrolytic copper bath formulations.
US patent application 2013/0043137 teaches the use of condensation products derived from triglycidylether compounds and amines in the electrolytic deposition of copper in recessed structures of minute circuit patterns and small holes such as blind via-holes and the like.
U.S. Pat. No. 6,610,192 relates to levelling agents derived from the reaction of cyclic amines with epihalohydrin to be used in electrolytic copper fillings of small voids.
U.S. Pat. No. 7,128,822 B2 describes the use of products formed by a three-component reaction of secondary or tertiary amines with glycols and spacer groups such as epichlorohydrin in the electrolytic deposition of copper in recessed structures. Said reaction products possess a dual-functionality as leveller and suppressor.
EP 1 619 274 B1 reports that the use of many of the above-mentioned levellers results in too rough copper surfaces (comparative examples 3 and 4 therein). The document suggests using more than one leveller in order to solve this issue. However, this is undesirable from the point of application.
The German patent DE 1 000 204 B relates to additives to be used in electrolytic copper deposition which bear a 1,3-Bis-(N,N′-alkylamino)-propan-2-ol moiety to increase the hardness of the formed copper alloys.
However, such additives in acidic copper plating baths are not suitable to fulfil the current and future requirements in manufacture of advanced printed circuit boards, IC substrates and metallization of semiconducting and glass substrates. Depending on the circuitry layout, BMVs' in printed circuit boards and IC substrates need to be filled with copper completely and not only conformally. Typical requirements for BMV filling are for example: obtaining a completely filled BMV while depositing no more than 10 to 15 μm of copper onto the neighbouring planar substrate areas and at the same time creating a dimple on the outer surface of the filled BMV of no more than 0 to 10 μm.
In metallization of semiconducting wafers, TSV filling must lead to a complete and void-free filling with copper while creating no more than ⅕ of via diameter of overplated copper onto the neighbouring planar areas. Similar requirements are demanded for filling through glass vias with copper.